package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.apache.tomcat.jni.Local;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.beans.BeanUtils;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.index.PathBasedRedisIndexDefinition;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.time.LocalDateTime;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;


@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private ISeckillVoucherService seckillVoucherService;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private RedissonClient redissonClient;
    private IVoucherOrderService proxy;//定义代理对象，提前定义后面会用到
    //注入脚本
    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }


    //异步处理线程池
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();


    //在类初始化之后执行，因为当这个类初始化好了之后，随时都是有可能要执行的
    @PostConstruct
    private void init() {
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    //创建线程任务，内部类方式
    private class VoucherOrderHandler implements Runnable {
        String queueName = "stream.orders";

        @Override
        public void run() {
            while (true) {
                //1.获取消息队列中的订单信息 xreadgroup group g1 c1 count 1 block 2000 streams streams.orders >
                try {
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    //2.判断消息获取是否成功
                    if (list == null || list.isEmpty()) {
                        //如果获取失败，说明没有消息，继续下一次循环
                        continue;
                    }
                    //3.解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //4.如果获取成功，可以下单
                    handleVoucherOrder(voucherOrder);
                    //5.ACK确认 SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while (true) {
                //1.获取pendingList的订单信息 xreadgroup group g1 c1 count 1 block 2000 streams streams.orders >
                try {
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    //2.判断消息获取是否成功
                    if (list == null || list.isEmpty()) {
                        //如果获取失败，说明pendingList没有异常消息，结束循环
                        break;
                    }
                    //3.解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //4.如果获取成功，可以下单
                    handleVoucherOrder(voucherOrder);
                    //5.ACK确认 SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理pending-list异常", e);
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException interruptedException) {
                        interruptedException.printStackTrace();
                    }
                }
            }
        }
    }

    /**
    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
    //创建线程任务，内部类方式
    private class VoucherOrderHandler implements Runnable{

        @Override
        public void run() {
            //1.获取队列中的订单信息
            try {
                VoucherOrder voucherOrder = orderTasks.take();
                //2.创建订单，这是调之前那个创建订单的方法，需要稍作改动
                handleVoucherOrder(voucherOrder);
            } catch (Exception e) {
                log.info("异常信息:",e);
            }
        }
    }
     */
    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        //1.获取用户
        Long userId = voucherOrder.getUserId();
        // 2.创建锁对象
        RLock redisLock = redissonClient.getLock("lock:order:" + userId);
        // 3.尝试获取锁
        boolean isLock = redisLock.tryLock();
        // 4.判断是否获得锁成功
        if (!isLock) {
            // 获取锁失败，直接返回失败或者重试
            log.error("不允许重复下单！");
            return;
        }
        try {
            //注意：由于是spring的事务是放在threadLocal中，此时的是多线程，事务会失效
            proxy.createVoucherOrder(voucherOrder);
        } finally {
            // 释放锁
            redisLock.unlock();
        }
    }



    /**
     * 实现秒杀下单
     * 与下面的代码要实现的差不多，只是这里基于lua去完成秒杀资格判断
     *
     * @param voucherId
     * @return
     */
    @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //获取订单id
        long orderId = redisIdWorker.nextId("order");
        // 1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),userId.toString(),String.valueOf(orderId)
        );
        int r = result.intValue();
        // 2.判断结果是否为0
        if (r != 0) {
            // 2.1.不为0 ，代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        //3.获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        //4.返回订单id
        return Result.ok(orderId);
    }

    /*
    @Transactional
    @Override
    public Result seckillVoucher(Long voucherId) {
        //1.查询优惠券信息
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        //2.根据优惠券的开始时间判断秒杀是否开始
        boolean isBegin = voucher.getBeginTime().isAfter(LocalDateTime.now());
        if (isBegin) {
            // 尚未开始
            return Result.fail("秒杀尚未开始");
        }
        // 3.判断秒杀是否已经结束
        boolean isBefore = voucher.getEndTime().isBefore(LocalDateTime.now());
        if (isBefore) {
            // 秒杀已经结束
            return Result.fail("秒杀已经结束");
        }
        // 4.判断库存是否充足
        if (voucher.getStock() < 1) {
            // 库存不足
            return Result.fail("库存不足！");
        }

        Long userId = UserHolder.getUser().getId();

        //获取锁对象
//        SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        RLock lock = redissonClient.getLock("lock:order:" + userId);

        //获取锁
        boolean isLock = lock.tryLock();
        //判断是否获取锁成功
        if (!isLock){
            //获取锁失败，返回错误或者重试
            return Result.fail("不允许重复下单!");
        }
        try {
            //获取代理对象（事务）
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        } finally {
            //释放锁
            lock.unlock();
        }
    }

     */

    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder){
        Long voucherId = voucherOrder.getVoucherId();
        //5.一人一单
        Long userId = voucherOrder.getId();
        //5.1查询订单
        int count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();
        //5.2判断是否存在
        if (count > 0){
            log.error("您已经购买过了");
        }
        //6.扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1")//set stock = stock -1
                .eq("voucher_id",voucherId).gt("stock",0) //where id = ? and stock > 0
                .update();
        if (!success){
            log.error("库存不足！");
        }
        this.save(voucherOrder);

    }
}

    

